1. Field of the Invention
This invention relates to cooling systems, specifically to a portable cooling unit using a magnet-driven vapor pump as the compressor portion of its refrigeration cycle, which can be easily transported from one place to another in a carrying bag to provide cooling for small areas and spaces. The vapor pump comprises an oil-filled block assembly, an elongated internal cylinder supported within the block assembly, and an elongated floating piston that is magnet-driven and rotates back-and-forth 180-degrees within the internal cylinder. Pivot points for the rotating piston are preferably single ball bearings which roll along spiral drive slots in the piston, and compression rings associated with the piston isolate compression and discharge functions. Lubrication for the spiral drive slots and bearings is provided by the oil-filled block assembly. The magnet-driven spiral vapor pump is in fluid communication with a condenser, a fixed-orifice metering device, and an evaporator to create the cycle of liquid/vapor phase changes for a refrigerant needed to provide cooled air for delivery to a targeted site, animal, or person. The condenser is positioned within a drain pan, and a fan positioned at one end of a mounting frame supported by drain pan moves air across the condenser and into an air discharge hose containing the evaporator, wherein after becoming cooled by the evaporator as it moves through air passageways therein, the air is directed through a hose terminal end fitting to the targeted area or space in need of cooling. The spiral vapor pump of the present invention has two compression chambers, and a magnetic pulse between electromagnets located at the opposite ends of the spiral vapor pump's block assembly pulls the floating piston so as to align the compression slot on one of its ends with a corresponding intake port in the internal cylinder to draw in vapor from the evaporator for compression, while concurrently aligning the compression slot on the piston's opposing end with a corresponding discharge port in the internal cylinder that releases a high-pressure vapor discharge to condensor coils. When the magnetic pulse rotationally pulls the piston 180-degrees in the opposite direction, the intake and discharge functions for its opposing ends are reversed. The magnetic force applied by the electromagnets to the opposing ends of the block assembly initiates rotational travel of the piston for compression, thus lowering the amount of battery power required for compression. Since batteries are not required to drive piston movement, and are only needed to power the present invention's magnetic control module and fan, battery life in the present invention is significantly extended when compared to prior art portable cooling units, allowing for longer periods of uninterrupted use. Also, portability of the present invention is enhanced, as a large supply of batteries is not required for extended operation. Contemplated applications of the present invention portable cooling unit are varied, and may include but are not limited to, medical applications and the cooling of small spaces, such as those surrounding children's strollers, play pens, wheel chairs, and pet carriers.
2. Description of the Related Art
Prior art portable air conditioning units have many disadvantages. They can be bulky and expensive to purchase, and when they are truly portable and run solely on battery power, they can be heavy to transport and their operating time is often significantly reduced. Yet even with these disadvantages, they are often used to cool infants, small children, the infirm, and caged pets who are not always able to take appropriate action on their own to remain comfortable. Thus, it continues to be desirable to find new ways to cool small spaces, such as those surrounding children's strollers, play pens, wheel chairs, and pet carriers. The simple construction of the present invention lowers cooling cost to the consumer, and the magnet-driven piston rotation occurring in its spiral vapor pump reduces power consumption to provide extended battery life during present invention operation over that currently available in other prior art portable cooling units.
While some prior art pumps have spiral components, no spiral components are known to drive the rotation of a piston back-and-forth 180-degrees for vapor compression. Also, no pump is known to have spiral drive components in combination with piston travel initiated by a magnetic force. A first example is the invention in U.S. Pat. No. 7,316,551 to Bohr (2008), which discloses a rotary vane suction pump with spiral inlet and outlet passages (see components numbered by 350, 352, 360, and 362 in FIGS. 24 and 25). Discs on the ends of its rotor close the ends of the pump chamber and the ends of radially directed slots in which the vanes are seated to form fluid cavities. In contrast, the structure of the present invention is different from that found in the Bohr invention, as its portable cooling unit does not have spiral inlet and outlet passages for the suction and discharge of fluid. Instead, pivot points for the back-and-forth 180-degree rotation of the present invention piston include spiral drive slots. In addition, a pump disclosed in U.S. Pat. No. 4,519,755 to Hanson (1985) has spiral paths for lubrication fluid travel into, and out of, its compression chambers for sealing purposes. The Hanson pump has an inner gear-type rotor mounted on a drive shaft which is off-center within an outer gear-type rotor (see column 2, lines 64-68). As the inner rotor is turned by an electric motor, intermeshing of rotor teeth causes the outer rotor to rotate within a rotor chamber. Since the inner rotor has one less gear tooth than the outer rotor, a pumping chamber is formed between each pair of rotor teeth. Oil enters the pumping chamber through the inlet port at one end of the pumping chamber, and exits through the outlet port at the other end of the same pumping chamber, thereby following a generally spiral path through the rotor assembly while it provides lubrication and sealing (see column 3, lines 55-61). In contrast, the structure of the present invention is very different from that found in the Hanson invention, as the spiral configuration in the present invention relates to spiral drive slots that provide pivot points for the back-and-forth 180-degree rotation of an elongated floating piston located within an internal cylinder, both of which are housed within an oil-filled block assembly, and its spiral features do not communicate with its “pumping chambers”. Furthermore, although spiral features are also found in other inventions, such as the invention in U.S. Pat. No. 5,209,650 to Lemieux (1993) which has spiral paths for introducing a liquid film to a shaft, the invention in U.S. in Pre-Grant Publication 2009/0229280 to Doty (2009) which discloses a spiral passageway that allows liquid refrigerant to cool a stator (see paragraph [0101]), and the invention in U.S. Pat. No. 5,245,958 to Krieg (1993) which has spiral grooves in a cylinder for venting purposes, none uses spiral drive slots as pivot points for rotation back-and-forth 180-degrees or has piston rotation that is magnet-driven. Thus, no other portable cooling unit is currently known with a vapor pump that functions in the same manner as the magnet-driven spiral-compression vapor pump of the present invention, or otherwise has a construction similar to that of the present invention portable cooling unit, or provides all of its features and advantages.